(1) Field of the Invention
The present invention generally relates to an organic electro-luminescence device, and particularly to an organic electro-luminescence device capable of blocking the hole.
(2) Description of the Prior Art
Recently, an organic electro-luminescence device has been studied a lot in the display technology. The organic electro-luminescence device can be used for manufacturing a thin-type display. Compared to a liquid crystal display, another kind of thin-type display, the organic electro-luminescence device is self-luminous, while the liquid crystal display still needs a backlight source. Therefore, the organic electro-luminescence device is able to achieve more saturated color reproduction easily.
Please refer to FIG. 1A. FIG. 1A is a cross-sectional side view of a conventional organic electro-luminescence device 10. The organic electro-luminescence device 10 usually in order includes a substrate 11, an anode layer 13, a hole injecting layer 15, a hole transporting layer 17, a light emitting layer 19, an electron transporting layer 21, an electron injecting later 23 and a cathode layer 25.
The combination of an electron and a hole in the light emitting layer 19 transforms electric energy into photon energy. As a result, light 29 is released and emits from the bottom of the substrate 11 of the organic electro-luminescence device 10. However, in this type of organic electro-luminescence device 10, the hole passes through the electron transporting layer 21 and moves toward the cathode layer 25. Therefore, the electron and the hole can not combine effectively in the light emitting layer 19, and the energy is wasted.
Please refer to FIG. 1B. FIG. 1B is a cross-sectional side view of another conventional organic electro-luminescence device 20. The difference between the organic electro-luminescence device 20 in FIG. 1B and the organic electro-luminescence device 10 in FIG. 1A is that the organic electro-luminescence device 20 further includes a hole blocking layer 22. The hole blocking layer 22 is disposed between the light emitting layer 19 and the electron transporting layer 21. The objective of the hole blocking layer 22 is to effectively block the, hole from moving toward the cathode layer 25. As a result, the electron and the hole combine in the light emitting layer 19 effectively. Therefore, the problem of the organic electro-luminescence device 10 in FIG. 1 is alleviated. However, though the organic electro-luminescence device 20 alleviates the energy wasting problem of the organic electro-luminescence device 10 in FIG. 1, the hole blocking layer 22 is added into the organic electro-luminescence device 20. As a result, the manufacturing process of the organic electro-luminescence device 20 becomes more complicated.
Therefore, the objective of the invention is to provide an organic electro-luminescence device with a simpler manufacturing process, higher luminance, greater efficiency and more saturated color reproduction.